The development of minimally invasive percutaneous procedures has yielded a major improvement in reducing recovery time and post-operative pain because minimal dissection of tissue (such as the psoas muscle tissue, for example) is needed. Minimally invasive surgical techniques are desirable for spinal and neurosurgical applications because of the need for access to locations within the body, and the danger of damage to vital intervening tissues and nerves.
Surgical procedures within the body, especially near the spine, require a set of dilators and a retractor to clear the tissue surrounding the spine before the spine can be accessed. An access procedure for a surgical operation begins with the insertion of a guide wire followed by a series of successively larger dilators installed in sequence to dilate the soft tissues such as the psoas muscle surrounding the spine. Then, following installation of the largest dilator deemed necessary, a retractor is advanced over the largest dilator for providing a working channel from the skin of the patient to working space adjacent the spine.
However, the set of conventional blunt dilators as described above has the potential to sever muscle fibers and irritate or otherwise disrupt the nerve roots which innervate the muscle tissue. This is especially true for dilating psoas muscle tissue to obtain access to the intervertebral disc space when performing a lumbar interbody fusion from a lateral approach.
Therefore, there is a need to provide an improved dilator and method for dilating the tissue with less muscle trauma and less damage to the nerve roots.